Traditionally, antimicrobial compounds are included in personal care or home care compositions to achieve disinfection of surfaces. When such compositions are of the wash-off type, the anti-microbial active does not have sufficient time available during the short period of time over which the washing is carried out, to ensure the desired activity. Further, the amount of anti-microbial active left on the surface after it has been washed off is low and therefore further possible antimicrobial efficacy is low.
The present applicant has disclosed in WO20100046238 that a composition comprising terpineol and thymol provides for enhanced germ reduction in fast acting time frames, in many cases in as low as 15 seconds after application of the composition on the desired surface.
One of the disadvantages of incorporating these actives especially thymol in sufficient quantities to ensure the desired fast acting antimicrobial activity is that the concentration at which thymol is used causes a strong medicinal odour to the composition which may not be liked by some people. Thus, there is a need to either reduce the concentration of this active or ensure that the odour impact is minimised.
The present inventors have been able to ensure the antimicrobial efficacy of these actives from wash-off compositions as well as enable it in leave-on compositions by incorporating these actives in a caged inorganic structure and providing sufficient stability during storage and thereby enhanced efficacy in use, by efficient coating of the particles using select materials. The invention thus ensures use of lower amount of antimicrobial actives, reduced issues like off-odour and enhanced antimicrobial efficacy. This invention, therefore has applications in products like soaps, detergents, shampoos, hand-wash products, hard-surface cleaning products, oral care products like toothpaste and toothpowders, and in leave on products like skin creams and lotions, hair gels, and sprays and products for use in household care applications.
Antimicrobial actives incorporated in zeolites have been reported. U.S. Pat. No. 5,010,109 (Chisso, 1991) discloses a novel antimicrobial, aromatic and deodorizing agent, a composition and a method of reducing microbial concentration or inhibiting microbial growth using the composition, which composition comprises a zeolite or porous glass carrier and a saturated monoterpene hydroperoxide as an active ingredient, the monoterpene hydroperoxide preferably selected from pinane hydroperoxide, thujane hydroperoxide, carane hydroperoxide, bornane hydroperoxide, paramenthane hydroperoxide, metamenthane hydroperoxide, and mixtures.
The published documents do not exhibit the enhanced delivery of the actives provided by the present invention. It is thus an object of the present invention to provide enhanced antimicrobial efficacy of the fast acting actives thymol and terpineol while ensuring that off-odours are masked during storage and use. The advantage of the present invention over published knowledge like in U.S. Pat. No. 5,010,109 is that antimicrobial actives thymol and terpineol which interact synergistically to provide antimicrobial activity are suitably encapsulated in a caged inorganic particle and suitably coated so as to minimize off odour when formulated in a personal care or cleansing composition while ensuring the desired fast antimicrobial activity when in use, by way of enhanced deposition on to the substrate.